Toy building block mold



FIG. 1 is a perspective view of a toy building block mold showing my new design;

FIG. 2 is a right end elevational view thereof;

FIG. 3 is a side elevational view thereof, the side opposite being substantially a mirror image;

FIG. 4 is a top plan view thereof;

FIG. 5 is a left end elevational view thereof; and,

FIG. 6 is a bottom plan view thereof. 

The ornamental design for a toy building block mold, as shown. 